Prepare for AllFrontend Interview Rounds

Evaluation Pointers

• Modularity & extendibility of the code — how you break a big problem into smaller problems and organize your code with separation of concerns and reusability. Extendibility tests whether new functionality requires a large rewrite.
• Best practices — how you incorporate frontend best practices for variables, functions, classes, and iteration.
• Overall functionality — interviewers generally prefer functionality over look and feel, but your application should meet all functional and non-functional requirements.

Essential Topics

• JavaScript Basics: Function, Object and Array Methods, closures, this keyword, iteration constructs, ES6 destructuring, spreading etc.
• Async JavaScript: Promises & its Methods, Async-Await, fetch API call, AbortController, setInterval, setTimeout etc.
• DOM & BOM: Accessing, modification and deletion of DOM elements, x/y location specific concepts etc.
• Concepts: Throttling, debouncing, template passing, exception & error handling etc.
• JavaScript Framework/React: Component creation, Hooks, props propagation, design patterns

Example Question

Evaluation Pointers

• Ability to evaluate the right output and explain under-the-hood working.
• Ability to explain how JS and JS framework fundamental concepts work, like closures, currying etc.

Essential Topics

• JavaScript Basics: Closures, "this" keyword, Currying, Hoisting, Prototypal Inheritance, Classes, Prototype chaining etc.
• Async JavaScript: Promises & its Methods, Async-Await, setInterval, setTimeout etc.
• JavaScript Framework/React: Design patterns like singleton, factory, hooks, pub-sub etc.

Evaluation Pointers

• Ability to drive the design discussion by covering all necessary questions and scoping.
• Ability to provide justifications and tradeoffs for choices made during system architecture and communication design.
• Knowledge about design patterns available to solve common frontend system design problems.

Essential Topics

• Virtualization/Windowing/Lazy Loading: To enable performant long list support
• Performance Optimization Techniques: Asset, network, and rendering optimizations
• Common Frontend Architecture: Micro-frontend, Monorepos, Monolithic
• Communication techniques: REST API, GraphQL, gRPC, tRPC
• Data Store Objects

Evaluation Pointers

• Ability to showcase in-depth knowledge about UI technologies, including browser, security, performance, and accessibility.
• Knowledge about use-cases, pros/cons, and general implementation in a web application.

Essential Topics

• Browser: How browser works, rendering of a webpage, JS engine etc.
• Security: Use-case and implementation of CORS, CSRF, CSP, XSS etc.
• Accessibility: Principles, accessibility roles and state (aria-*) etc.
• Performance improvement techniques: Asset, network, and rendering optimizations
• Authentication: Basic Auth, OAuth2.0, JWT token, OpenID connect etc.

Evaluation Pointers

• Problem-solving approach: How you break down a problem and identify the right data structure and algorithm to use.
• Code efficiency: Ability to write optimized code with good time and space complexity.
• Edge case handling: How well you identify and handle edge cases and boundary conditions.

Essential Topics

• Arrays & Strings: Manipulation, searching, sorting, two-pointer technique, sliding window etc.
• Hash Maps & Sets: Frequency counting, caching, lookup optimization etc.
• Trees & Graphs: DOM tree traversal, component hierarchy, BFS, DFS etc.
• Recursion & Backtracking: Tree operations, nested structures, memoization etc.
• Time & Space Complexity: Big-O notation, optimization techniques, trade-offs etc.